Dynamic Ron Effect in GaN HEMT in a Zero-Voltage-Switching Circuit Due to Off-Resonance Operation

Abstract

Dynamic ON resistance of GaN devices is a must-care point for users. In this paper, the reverse conduction of commercial GaN power transistors is studied. Even though the commercial HEMTs show stable performance in normal operation modes (off-to-on), significant dynamic ON resistance can be seen in some particular conditions. A test method is set up to evaluate dynamic Ron in a reverse-to-on mode. The conditions to activate the behavior are discussed, and the cause of dynamic Ron is possibly due to traps located in the gate region. Meanwhile, a wireless power transfer system operating at 6.78MHz is used to study the effect of reverse conduction mode on dynamic resistance at the circuit level. According to the change of the operation frequency, we find that the influence of reverse conduction on the dynamic Ron effect is not only affected by the value of reverse conduction voltage but also related to the operating mode of the device.

Keywords

• GaN
• dynamic resistance
• wireless power transfer
• reverse conduction